At about 300 meters across, scientists said it would explode with the force of about 500 megatons were it to hit our planet.

The asteroid was already famous, after a 2004 report said there was a one in 45 chance of it hitting us in 2029.

While it is set to come extremely close to us in that year, passing within 32,000 km of Earth - nearer than many satellites - is was already known the asteroid would miss us on that occasion.

However, it had been thought there was still a non-trivial chance of the rock hitting us in 2036 - about a one in 200,000 probability.

But after fresh observations this week, that has now dropped to essentially zero.

"The impact odds as they stand now are less than one in a million, which makes us comfortable saying we can effectively rule out an Earth impact in 2036," Don Yeomans, manager of Nasa's Near-Earth Object Program Office, said in a statement.

However, while that threat is over - for now - there's no reason to stop watching the skies.

Nasa's Near Earth Object program is already tracking more than 9,000 objects, and says that many thousands more are still unknown.

As such, if an asteroid were to emerge on a collision course with Earth, it's probable we wouldn't know about it until it was too late.